title: Evaluation of immune functions in captive immature loggerhead sea turtles (Caretta caretta).
abstract: Sea turtles face numerous environmental challenges, such as exposure to chemical pollution and biotoxins, which may contribute to immune system impairment, resulting in increased disease susceptibility. Therefore, a more thorough assessment of the host's immune response and its susceptibility is needed for these threatened and endangered animals. In this study, the innate and acquired immune functions of sixty-five clinically healthy, immature, captive loggerhead sea turtles (Caretta caretta) were assayed using non-lethal blood sample collection. Functional immune assays were developed and/or optimized for this species, including mitogen-induced lymphocyte proliferation, natural killer (NK) cell activity, phagocytosis, and respiratory burst. Peripheral blood mononuclear cells (PBMC) and phagocytes were isolated by density gradient centrifugation on Ficoll-Paque and discontinuous Percoll gradients, respectively. The T lymphocyte mitogens ConA significantly induced lymphocyte proliferation at 1 and 2 μg/mL while PHA significantly induced lymphocyte proliferation at 5 and 10 μg/mL. The B lymphocyte mitogen LPS significantly induced proliferation at 1 μg/mL. Monocytes demonstrated higher phagocytic activity than eosinophils. In addition, monocytes exhibited respiratory burst. Natural killer cell activity was higher against YAC-1 than K-562 target cells. These optimized assays may help to evaluate the integrity of loggerhead sea turtle's immune system upon exposure to environmental contaminants, as well as part of a comprehensive health assessment and monitoring program.
authors.affiliation: Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, 1207 Gilbert Drive, Lubbock, TX 79416, United States. Electronic address: estelle.rousselet@vetagro-sup.fr.
authors.forename: Estelle
authors.initials: E
authors.lastname: Rousselet
authors.forename: Milton
authors.initials: M
authors.lastname: Levin
authors.forename: Erika
authors.initials: E
authors.lastname: Gebhard
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Higgins
authors.forename: Sylvain
authors.initials: S
authors.lastname: DeGuise
authors.forename: Céline A J
authors.initials: CA
authors.lastname: Godard-Codding
mesh_terms: D056704:Adaptive Immunity; D000818:Animals; D005434:Flow Cytometry; D007113:Immunity, Innate; D007962:Leukocytes / Q000276:immunology; D008213:Lymphocyte Activation; D010587:Phagocytosis; D014426:Turtles / Q000276:immunology*
keywords: Caretta caretta; Lymphocyte proliferation; Mitogen; Natural killer; Phagocytosis; Respiratory burst; Sea turtle